Impacts of climate change

Warm up

Antarctica has experienced air temperature increases of 3°C in the Antarctic
Peninsula Although that might not seem very much, it is 5
times the mean rate of global warming as reported by the Intergovernmental
Panel on Climate Change (IPCC).

Over the past 50 years, the west coast of the Antarctic Peninsula has
been one of the most rapidly warming parts of the planet. This warming
is not only restricted to the land but can also be noted in the Southern
Ocean. Upper ocean temperatures to the west of the Antarctic
Peninsula have increased over 1°C since 1955. It has now been established
that the Antarctic Circumpolar Current is warming more
rapidly than the global ocean as a whole. Studying climate change in
Antarctica is important because it enables scientists to predict more
accurately future climate change and provide information to politicians
and policy makers.

The warming of the Antarctic Peninsula is causing changes to the physical
and living environment of Antarctica. The distribution of penguin colonies
has changed as the sea ice conditions alter. Melting of perennial snow
and ice covers has resulted in increased colonisation by
plants. A long-term decline in the abundance of Antarctic krill in
the SW Atlantic sector of the Southern Ocean may be associated with reduced
sea ice cover. Large changes have occurred in the ice cover of the Peninsula.
Many glaciers have retreated and ice shelves that formerly fringed the
Peninsula have been observed to retreat in recent years and some have
collapsed completely.

Cold Facts

Impacts on ice

Ice shelves are the floating extensions of a grounded ice sheet. One
of the largest ice shelves, the Ronne-Filchner covers an area slightly
smaller than Spain. Each summer, a significant amount of meltwater is
produced which can only be tolerated so long before the ice shelf will
weaken and retreat. Climate in the Antarctic Peninsula
has warmed by 3°C meaning that once stable ice shelves are now retreating.
Since the 1950s this is a loss of 25,000 km2 of ice shelf.

Impacts on wildlife: penguins

There are about 20 million breeding pairs of penguins in the Antarctic.
Some species of penguins in Antarctica are declining in numbers while
others are not. The picture varies depending on where in Antarctica you
are looking. Adélie penguins, a species well adapted to sea ice
conditions, have declined in numbers in some areas and have been replaced
at some sites by open-water species such as chinstrap penguins. Further
south, emperor penguins, which breed on sea ice surrounding continental
Antarctica, have also experienced a decline in numbers by up to 50% in
places.

Impacts on marine life: krill

Results published by the British Antarctic Survey in 2004 highlighted
that Antarctic krill numbers are declining. Krill are very important
to the Antarctic food web and this decline could threaten
whales, seals and penguins all of which feed on krill. The decline of
krill has been linked to a dramatic decline in sea ice. Sea ice is a
vital feeding ground for the huge number of krill in the Southern Ocean.
The research shows that krill numbers have dropped by about 80% since
the 1970s. Less sea ice during the winter is likely to be the cause and
may explain declines seen in several species of penguins. Krill feed
on the algae found under the surface of the sea ice, which acts as a
kind of 'nursery'. The Antarctic Peninsula, a key breeding ground for
the krill, has experienced a striking decrease in sea ice.

Impacts on sea level

Although Antarctica is many thousands of miles away from most of us,
the impacts of climate change are not only confined to the shores of
the icy continent. Scientists fear that water that is currently stored
in ice on land (including ice sheets but not ice shelves) may melt and
contribute to sea level rise. Satellite measurements since the early
1990s indicate that sea level is rising at a rate of 3mm per year and
indeed sea level has been rising over the last century. However, the
Intergovernmental Panel on Climate Change (IPCC) are not able to confirm
confidently at present what contribution the melting of ice sheets will
have on sea level over the coming centuries. There is a possibility that
sea level rise could be higher than the IPPC estimates suggest.